1. Field of the Invention
The present invention relates to a method for manufacturing a resin-sealed type semiconductor device that performs transfer molding.
2. Background Art
Lead frames are formed by punching them out from a metal sheet by means of a progressive die. In that case, a burred surface, fracture surface and rolled-over surface are provided on a side of the lead frame. The presence of this fracture surface or the like strengthens the adhesion of the resin burr to the lead frame, and it is therefore difficult to remove the resin burr.
Thus, a method is proposed which provides a substance having a low level of adhesion to the mold resin in a dam segment to improve resin burr removing characteristics (e.g., see FIG. 11 of Japanese Patent Laid-Open No. 4-164356). However, resin burr cannot be easily removed using this method, either. There is also a problem that this method takes time and cost, and it is hard to incorporate the method into actual manufacturing steps.
On the other hand, another method is proposed which removes a burred surface or fracture surface by vertically shaving a side of the lead frame (e.g., see Japanese Patent Laid-Open No. 2-202045). This allows resin burr to be easily removed.